ROSS CONTROLS. Pneumatic Reference Data. TABLE OF CONTENTS

Transcription

1 ROSS CONTROLS Pneumatic Reference Data TABLE OF CONTENTS Page PNEUMATIC PRINCIPLES... 3 GLOSSARY OF USEFUL TERMS... 4 VALVE RESPONSE TIME FLOW COEFFICIENTS... 6 STANDRDIZED TESTING... 6 FLOW CHART FOR C v =... 7 CYLINDER VOLUME... 8 VALVE SIZING... 9 PNEUMATIC SYMBOLS... 0 PORT IDENTIFICATION... CONVERSION FACTORS... CAUTIONS, WARNINGS and STANDARD WARANTY...Outside Cover

2 PNEUMATIC PRINCIPLES Pneumatics is the study of the mechanical properties of gases. In industrial applications the gas involved is most commonly compressed air. The mechanical properties with which we are most concerned are pressure, volume and temperature. The relationships between these properties, and the meanings of some basic pneumatic terminology are discussed below. Force and Pressure. Piston area Consider the diagram 4 sq in of the cylinders on 60 lb the right. When the force of 60 pounds is 60-lb applied to the piston, upward force resulting from the air in the cylinder compression is compressed. This compression continues until the upward force on Figure the piston is the same as the downward force, that is, until the forces are in equilibrium. The force on each square inch of the piston is: force on piston = 60 lb = 5 lb per in (psi) area of piston 4 in This force per unit area is called pressure. The terms force and pressure must not be confused. Force is expressed in units such as pounds, tons, kilograms, etc., while pressure is expressed as pounds per square inch, tons per square mile, kilograms per square meter, etc. In general terms, then: pressure = force area Conversely, the force exerted on or by an area is: force = pressure x area Pascal s Law. Pressure applied to a confined fluid is transmitted undiminished in all directions. In the discussion of Figure we learned that the force applied to the piston produces a pressure of 5 psi (pounds per square inch). Pascal s Law simply says that a pressure of 5 psi is applied to all surfaces containing the air, i.e., the walls and bottom of the cylinder as well as the piston surface itself. Atmospheric Pressure. The pressure produced on the earth's surface by the weight of the air surrounding the earth was measured by the 7th-century scientist, Evangelista Torricelli. He filled a 36-inch glass tube (sealed at one end) with mercury, and placed his finger over the open end of the tube. He then stood the tube on end in a dish of mercury and removed his finger. Some mercury flowed from the tube into the dish, but a column of mercury 30 inches tall remained in the tube. The pressure of the atmosphere, 30" Hg Figure Vacuum he reasoned, is sufficient to support a column of mercury 30 inches high. More refined tests have shown this atmospheric pressure to be equal to 4.69 pounds per square inch. Gauge Pressure. Atmospheric pressure is a part of our everyday environment. We don t notice the pressure on us, and it is convenient to think of atmospheric pressure as zero pressure. So we measure pressure starting at this zero point, and a pressure so measured is called gauge pressure. A common abbreviation for gauge pressure measurements is psig (pounds per square inch gauge). Absolute Pressure. When dealing with the effects of pressure on gases it is necessary to consider the total pressure on the gas. We can no longer ignore the effect of atmospheric pressure as we do when we measure gauge pressure. This total pressure acting on a gas is called absolute pressure. absolute pressure = gauge pressure You will recognize 4.69 as the pounds-per-square-inch measure of atmospheric pressure. To distinguish absolute pressure from gauge pressure measurements, we use units such as psia (pounds per square inch absolute). Absolute Temperature. Absolute temperature is based on a theoretical lowest temperature. This lowest temperature is the zero point for the two absolute temperature scales in common use, the Rankine scale and the Kelvin scale. The Rankine scale is based on the Fahrenheit degree. Rankine temperature = Fahrenheit temperature Thus, 0 F = R, although for most practical applications it is taken as 460 R. The Kelvin scale of absolute temperature is based on the Celsius degree. Kelvin temperature = Celsius temperature Thus, 0 C = 73.6 K. Again, for most practical purposes it is taken as 73 K. Perfect Gas Laws. The relationships between pressure, volume, and temperature are expressed in three basic laws which we will discuss below. These laws apply to an ideal gas, but are also remarkably accurate for the mixture of gases making up our air. In applying these laws it is important to remember that only absolute values of pressure and temperature may be used. Boyle's Law. This law expresses the relationship between pressure and volume when temperature is held constant. According to this law, the volume of the gas in a container is inversely proportional to the absolute pressure on the gas, i.e., V = P V Let us apply this law to find the volume of the gas in the cylinder below (Figure 3) after compression. m The pressure acting on the cylinder at the left is simply atmospheric pressure. The absolute pressure on the cylinder after it is compressed is: P = (60 4) = 9.7 psia = 4.7 psia Piston area 4 sq in 60 lb With this information we can use Figure 3 Boyle's Law to find the compressed volume. 4.7 x 0 = 9.7 x V V = 4.7 x = 59.4 cubic inche When a gas is compressed it gets warmer, so the above calculation would be correct only after the compressed gas has been allowed to cool to the temperature it had before compression. V 0 cu in P V 06, ROSS CONTROLS. All Rights Reserved.

3 PNEUMATIC PRINCIPLES Charles Law. This law expresses the relationship between volume and temperature when pressure is held constant. According to this law, the volume of the gas in an expandable container is directly proportional to the absolute temperature of the gas, i.e., V T = V T Let us take the cylinder in Figure 3 and specify that the temperature of the gas is 60 F. If we apply heat to the container, as depicted in Figure 4 below, so that the temperature of the gas is raised to 00 F, what will be the new volume of the gas. Note that the load on the piston does not change, and therefore the pressure on the gas is constant as required by Charles Law. The absolute temperatures are: T = 60 F + 460F = 50 R T = 00 F + 460F = 560 R The volume of the compressed gas as we determined it from Figure 3 is V = 59.4 cubic inches. When we apply Charles Law to this information we have: 59.4 x 560 = V x 50 V = 59.4 x lb 60 lb = 64.0 cubic inches Gay-Lussac s Law. The third gas law states that if the volume of a gas is held constant (i.e., confined in a rigid container) the absolute pressure of V T V T the gas is directly proportional to its absolute temperature. Thus, T = P T Figure 4 A closed container when heated builds up considerable internal pressure, and can lead to an explosion of the container. This is Gay-Lussac s Law at work! General Gas Law. In practical applications all three of the variables pressure, volume, temperature may change. The three gas laws we have discussed can be consolidated into a single general law which provides for changes in all three variables. This general law is simply: V T = P V T Let us apply this general law to the following problem. General Gas Law. In practical applications all three of the variables pressure, volume, temperature may change. The three gas laws we have discussed can be consolidated into a single general law which provides for changes in all three variables. This general law is simply: V T = P V T Let us apply this general law to the following problem. Initially, the force on the cylinder s piston is 400 lb. This compresses the gas in the cylinder to a volume of 0 cubic inches at a temperature of 60 F. If the gas in the cylinder is heated to 00 F, what force must be on the piston to compress the gas further to a volume of 00 cubic inches? 400 lb Piston area 4 sq in 0 cu in 60 F Figure 5? lb 00 cu in 00 F Because the piston has an area of 4 square inches, the absolute pressure on the gas initially is: = (400 4) = 4.7 psia, and the absolute temperatures are: T = = 50 R T = = 660 R. In order to determine the force that must be on the piston in order to compress the heated gas to 00 cubic inches, we must first find the value of P. To do this we apply the general gas law, V T = P V T. 4.7 x 0 x 660 = P x 00 x 50 P = (4.7 x 0 x 660) (00 x 50) = 74.7 psia P in terms of the force F acting on the piston is: P = (F 4) Then we have, 74.7 = (F 4) F 4 = = 60 psig F = 60 x 4 = 640 lb. Standard Air and Free Air. In the United States the volume of air is most commonly measured by the cubic foot. Of course the actual amount of air in a cubic foot depends on factors such as pressure and temperature, so it has become necessary to define a standard cubic foot (scf) of air. For most industrial applications this is a cubic foot of air at a pressure of one atmosphere (4.69 psia), a temperature of 68 F, and a relative humidity of 36 per cent. The weight of a standard cubic foot of air is lb; lb of standard air occupies 3. cubic feet. In actual practice one seldom encounters standard air, but is dealing with free air, that is, the air that we encounter in everyday experience. Fortunately, unless we are on a mountaintop or working near a blast furnace, free air is close enough to standard air so that we do not have to make corrections for the small differences. Compressed Air. The flow of air through a valve or any part of a pneumatic system is usually measured in standard cubic feet per minute (scfm). Often it is necessary to know what this volume of air is when compressed. Boyle s law solves the problem easily. For example, if the air flow through a valve is 50 scfm, what is the actual volume of the air if the pressure is 00 psig? Remembering that Boyle s law requires that we use absolute pressures, we have: 4.7 x 50 = ( ) x V where V is the volume of the compressed air, we obtain: V = (4.7 x 50) ( ) V = 6.4 cubic feet per minute. Conversely, we could ask for the pressure required to fill an automobile tire with cubic feet of free air if the tire has a volume of 0.5 cubic foot. Again, from Boyle s law we obtain: 4.7 x = (P + 4.7) x 0.5 where P is the gauge pressure required to fill the tire. P = (4.7 x ) 0.5 P = 58.8 P = 44. psig. 3

4 GLOSSARY OF USEFUL TERMS Absolute Pressure: The sum of atmospheric pressure and gauge pressure. Designated as psia (pounds per square inch absolute). Air Receiver: A container in which air is stored under pressure as a source of pneumatic power. Ambient Temperature: The temperature of the immediate environment. Atmospheric Pressure: The pressure exerted by the atmosphere. At sea level this pressure is 4.69 pounds per square inch absolute. Bar: A unit of pressure measurement equal to 0 5 newtons per square meter or 4.50 pounds per square inch. Celsius, Degree: A unit of temperature measurement abbreviated C. Celsius temperatures are calculated from Fahrenheit temperatures by the following formula: C= 5(F-3) 9 Closed Center: Pertains to three-position valves; all ports are closed when the valve is in the center position. Detent: A device for retaining movable parts in one or more fixed positions; usually a spring-loaded device fitting into a depression. Positions of parts are changed by exerting sufficient force to overcome the detent spring, or by releasing the detent. Directional Control Valve: A valve whose function is to direct or prevent flow through selected passages. Flow Rate: The volume or weight of a fluid passing through a conductor per unit of time. For pneumatic systems, flow rate is most often expressed as standard cubic feet per minute (scfm). Fluid: A liquid or a gas. Fahrenheit, Degree: A unit of temperature measurement abbreviated F. Fahrenheit temperatures are calculated from Celsius temperatures by the following formula: F =.8C + 3 Four-Way Valve: Now designated as a 4/ valve; a four-port, two position valve. Free Air: Air at atmospheric pressure. Gauge Pressure: Pressure above or below atmospheric pressure. Designated as psig (pounds per square inch gauge). Holding Power: Amount of electric power required to maintain solenoid in its actuated position. Impulse Signal: A briefly applied pneumatic or electric signal; a momentary signal. Inrush Power: Amount of electric power required during time solenoid plunger is moving. Media: The fluids used in a fluid power system. In a pneumatic system they are gases such as air, nitrogen, or various inert gases. Media Temperature: The temperature of the fluid within a valve or other device. Micron: A measurement equal to one-millionth of a meter or about inch. Momentary Signal: A briefly applied pneumatic or electric signal; an impulse signal. Normally Closed: A term used to describe a valve which blocks the flow of supply air when the valve is not actuated. Normally Open: A term used to describe a valve which allows supply air to flow only when the valve is not actuated. Open Center: Pertains to three-position valves; outlet ports are connected to exhaust when valve is in the center position. Pressure: A measure of force per unit area; often expressed as pounds per square inch (psi) or bar. Pressure Range: The range of inlet pressures with which a device can operate satisfactorily. Signal: A fluid or electric command to the valve actuator causing the valve to change position. Silencer: A device used to reduce the sound level produced by an exhausting gas. Standard Air: Air at a temperature of 68 F, a pressure of 4.69 pounds per square inch absolute (psia), and a relative humidity of 36 per cent ( pounds per cubic foot). In gas industries the temperature of standard air is usually specified as 60 F. Three-Way Valve: Now designated as a 3/ valve; a three-port, two-position valve. Two-Way Valve: Now designated as a / valve; a two-port, two-position valve. Also know as a straightway valve. Vacuum: Pressure less than atmospheric pressure. VALVE RESPONSE TIME Most pneumatic applications call for a valve to be used to control the repeated filling and exhausting of a device (cylinder, clutch, etc.) having a certain volume. The time required to fill or exhaust this volume is called the valve response time. The time to fill a volume is usually different from the time to exhaust the volume. Both times can be found by using the following formula: Valve Response Time = M + (F V) This formula gives the time in milliseconds (msec = 0.00 sec) required to fill the volume V to 90% of supply pressure or to exhaust the volume V to 0% of supply pressure. M and F are average response constants, and their values for each valve are found in the ROSS master catalog. V is the number of cubic inches in the volume to be filled or exhausted. What is the constant M? When a valve is energized it takes a number of milliseconds for the valve to shift and allow a steady flow of air to be established at the outlet port. In like manner, when the valve is de-energized it takes a number of milliseconds for the valve to shift and cut off the flow of outlet air and establish the flow of exhaust air. These valve movement times are designated by M in the above formula. What is the constant F? After the valve has shifted and air flow to fill the volume V is established, the air flows rapidly at first, then flows at a reducing rate as pressure builds up in the volume V. In exhausting the volume V, air flows rapidly at first, then at a reducing rate as the pressure falls in the volume V. In either case the average flow rate is represented in the above formula by F. It is the average number of milliseconds required to fill or exhaust one cubic inch of the volume V. The product F V, then, is the number of milliseconds required to fill or exhaust the entire volume V after the valve has shifted. The F values for each valve are found in the ROSS master catalog, and they are generally different for the filling and exhausting functions. The response time tables list the F values under the headings In-Out and Out-Exh. Clearly the values under the In-Out heading are to be used when a volume is being filled, and the values under the Out-Exh heading are used when a volume is being exhausted. 4 06, ROSS CONTROLS. All Rights Reserved.

5 VALVE RESPONSE TIME Use of the valve response time formula is illustrated by the following problems. Problem A: How long will it take to fill a 00-cubic-inch chamber to 90% of supply pressure using an ISO size metal spool valve with single solenoid control? Solution A: Average response constants for this valve are found in the ROSS master catalog. For the size series W60 (metal spool) valve the values are M = 4 and F =.5. The F value of.4 is for the exhaust paths and so is not needed for this problem. Putting these M and F values into the valve response time formula we have: Average Response Time = 4 + (.5)(00) = = 9 msec The volume of 00 cubic inches would be filled to 90% of supply pressure in 9 milliseconds, or less than /0 of a second. Problem B: What Series 7, normally closed, 3/ valve is needed to fill a 000-cubic-inch volume to 90% of supply pressure in less than / second (500 msec)? Solution B: Put the given data into the basic formula: 500 = M + (F 000) Now we must find the values of M and F that make the right-hand side of the equation less than 500 msec. We can shorten our work by noting that the dominant quantity in the formula is F 000. Therefore we must find a value of F that will make F 000 less than 500, i.e., F must be less than 0.5. In the ROSS master catalog we find the response time constants for Series 7, 3/, normally closed valves. The first F value that is less than 0.5 is The M value is. Putting these values into the basic formula we obtain: Average Response Time = + (0.43)(000) = = 44 msec We see that the valve to be selected is the larger of the two /-inch valves. In the ROSS master catalog we identify this valve as model number 773B400. FLOW COEFFICIENTS The flow coefficient (C v ) of a pneumatic device is a measure of the device's ability to pass air. The amount of air that can flow through various valves, for example, is in direct proportion to the sizes of their flow coefficients, for given inlet and outlet pressures. Air flow through a valve (or other device) is measured in the laboratory under carefully controlled conditions. From this measurement plus measurements of the inlet and outlet pressures, the flow coefficient can be determined. The relationship between these factors at a temperature of 68 F (0 C) is expressed in the following formula: Q = 0.98 C v Δ P(P + 4.7) where Q = air flow in standard cubic feet per minute (scfm) C v = flow coefficient = inlet pressure (psig) P = outlet pressure (psig) ΔP = pressure drop across valve (psi) = P Knowing the flow coefficient and the inlet and outlet pressures, the flow through a valve can be determined using this formula. A simpler way, however, to determine air flow is to use the graph on the page 6. This graph is based on the above formula when C v =. Since air flow is proportional to C v, this graph can be used for any C v value; simply multiply the air flow rate given on the graph by the new C v value. Example: Given a supply pressure of 5 psig, a pressure drop of 7 psi, and a valve with a C v of 4., find the rate of air flow through the valve. From the 7 psi pressure drop value at the bottom of the graph, move upward to the supply pressure line for 5 psig. From this point move to the left and read the air flow rate: 30 scfm. Since this is the air flow rate for C v =, multiply by 4. to obtain the air flow rate for the valve in this example. 30 x 4. = 6 scfm. Determining the C v Required of a Valve Operating a Cylinder: The charts on pages 7 and 8 can be used to determine the valve C v required to operate cylinders of various sizes. The chart on page 7 shows the displaced volume of cylinders with various strokes and diameters. Knowing the volume of the cylinder and the number of strokes per minute the cylinder must make, the chart on page 8 can be used to determine the minimum C v that the operating valve must have. Parallel Connection of Pneumatic Components: If several pneumatic components are connected in parallel, the flow coefficient of the combination is simply the sum of the flow coefficients of the several units. For example: C v C v C v3 Combined C v = C v + C v + C v3 Series Connection of Pneumatic Components: If several pneumatic components are connected in series, the flow coefficient of the combination is a little more complicated. For example: C v C v C v3 Combined C v : = + + (C v) (C v) (C v ) (C v3 ) Using C v values must always be tempered with good judgement. Flow coefficients are determined in the laboratory under steady flow conditions, a state that exists only part of the time in an industrial pneumatic system. Some allowance must be made for the valve response time required to establish steady flow conditions. (See discussion of Valve Response Time on page 4 and 5.) The use of C v values is just one area in which the experience and judgement of the pneumatic designer become important. 5

6 STANDARDIZED TESTING The illustration below shows a standardized test set-up established by the American National Standards Institute. ROSS engineering practice calls for strict adherence to the new testing standards established by ANSI. The adoption of the new ANSI testing standards by the pneumatics industry will be a major step forward in eliminating the confusion about C v ratings which has sometimes existed. Acceptable variations in instrumentation and test hookup can still yield variations up to 5 per cent in C v values. However, this will still represent a major improvement over the extreme variations which have sometimes existed in the past. 0 = upstream temperature = pressure at upstream tap ΔP = pressure drop D = inside diameter of conductor FLOW CHART FOR Cv = 6 06, ROSS CONTROLS. All Rights Reserved.

7 CYLINDER VOLUME

8 VALVE SIZING , ROSS CONTROLS. All Rights Reserved.

9 FLUID CONDUCTORS Working Line Exhaust Line or Control Line Lines Crossing VALVES PNEUMATIC SYMBOLS Single Square (Unit for controlling flow. Contains information on porting and flow paths.) One Flow Path Two Closed Ports FLUID CONDITIONERS Basic Envelope (Filters and lubricators) Filter (Manual drain) Filter (Automatic drain) Lines Connected Two Flow Paths or Lubricator (Less drain) Mechanical Connection (Shaft, Rod, etc.) Fixed Restriction Variable Restriction Two Flow Paths & One Closed Port Two Flow Paths with Cross Connection One By-pass Flow Path & Two Closed Ports Two External Ports Lubricator (Manual drain) Air Dryer Pressure Regulator (Adjustable, self-relieving) Flexible Line Plugged Port Direction of Flow ENERGY SOURCES -Position Envelope 3-Position Envelope Two Distinct Positions & One Transitory (center) Position / Valve Ports, Positions Pressure Regulator (Adjustable, non-relieving) ACTUATORS and CONTROLS Detent Position Vertical line indicates flow position. Pneumatic (Any fluid power source) 3/ Valve 3 Ports, Positions Muscular Control Compressor (Fixed displacement) 4/ Valve 4 Ports, Positions Push-button Vacuum Pump (Fixed displacement) 5/ Valve 5 Ports, Positions Lever Accumulator 4/3 Valve 4 Ports, 3 Positions 5/3 Valve 5 Ports, 3 Positions Pedal or Treadle Plunger or Position Indicator Pin Spring 9

10 ACTUATORS and CONTROLS PNEUMATIC SYMBOLS ENERGY CONVERSION SPECIAL PURPOSE VALVES Roller Roller - One way Solenoid Single winding Solenoid Two opposite windings Variable Solenoid Two opposite windings Pilot Pressure External Pilot Pressure Internal Release of Internal Pilot Pressure Interior Control Path Solenoid or Internal Pilot Solenoid or External Pilot Solenoid plus Internal Pilot Two External Pilots Cylinder Spring return Cylinder Unspecified return Cylinder Double Acting Single rod Cylinder Double Acting Double rod Cylinder Double Acting Single fixed cushion Cylinder Double Acting Two adjustable cushions Quick Acting Coupling Quick Acting Coupling With mechanically opened non-return valve Quick Acting Coupling Not coupled, with open end Quick Acting Coupling Not coupled; closed by free non-return valve Check Valve Non-return Check Valve Spring loaded Flow Control Valve Shuttle Valve Sequence Valve Shutoff Valve MEASURING INSTRUMENTS and SWITCHES Pressure Gauge Pressure Actuated Electric Switch Flow Gauge Solenoid & Pilot or Manual Override Solenoid & Pilot or Manual Override and Pilot Silencer Air Motor One directional flow Differential Pressure Air Motor Two directional flows 0 06, ROSS CONTROLS. All Rights Reserved.

11 PORT IDENTIFICATION The port markings on ROSS valves are the same as those shown on the valve symbols in ROSS literature. Main ports are identified by numbers, except for SAE valves which continue to use letters for identification. Older valves may not have numerical port markings. The correspondence between the older markings and the current numerical markings is shown below. Current Port Marking Previous Port Marking IN, P OUT, OUT A, CYL, CYL A 3 EXH, EA, R 4 OUT, OUT B, CYL, CYL B 5 EXH, EB, S CA 4 CB Main Port Identification. Numbers through 5 are used for main port identification as follows: Normal inlet port. Normal outlet port. & 4 Normal outlet ports where two are provided. 3 Normal exhaust port. 3 & 5 Normal exhaust ports where two are provided. Pilot Control Identification. The following numbers are used on symbols for pilot control or control port identification. When an electrical or pneumatic signal is applied to the control or port, the following conditions result: 0 Inlet is closed. Inlet is connected to outlet. 4 Inlet is connected to outlet 4. Use of some of the above controls are shown in the following examples. Example. / ( port, position) normally open, spring return valve. Valve not actuated. Valve actuated by pneumatic signal applied to port 0. Example. 3/ (3 port, position) normally closed, spring return valve. Valve not actuated. Valve actuated by electrical signal applied to control. Example 3. 4/ (4 port, position) spring return valve. Valve not actuated. Valve actuated by pneumatic signal applied to control Example 4. 5/3 (5 port, 3 position) closed center, spring centered valve. Valve in non-actuated center position. Valve actuated by electrical signal applied to control. Valve actuated by electrical signal applied to control 4. Auxiliary Ports for Pilot Operators Port Function X X Y Y3 Y4 } } External pilot supply port Exhaust port for solenoid pilot Example: Y4 5 3 CONVERSION FACTORS U.S. to Metric Conversion From To Multiply By inches...millimeters feet...meters miles...kilometers square feet...square meters cubic feet...cubic meters cubic feet...liters gallon...liters pounds...kilograms lb/in (psi)...bar ft 3 /min...liters/second (l/s) millimeters...inches meters...feet kilometers...miles square meters...square feet cubic meters...cubic feet liters...cubic feet liters...gallons kilograms...pounds...05 bar...lb/in liters/second (l/s)...ft 3 /min...0 X 4 3

12 CAUTIONS, WARNINGS and STANDARD WARRANTY PRE-INSTALLATION or SERVICE. Before servicing a valve or other pneumatic component, be sure that all sources of energy are turned off, the entire pneumatic system is shut off and exhausted, and all power sources are locked out (ref: OSHA 90.47, EN 037).. All ROSS products, including service kits and parts, should be installed and/or serviced only by persons having training and experience with pneumatic equipment. Because any installation can be tampered with or need servicing after installation, persons responsible for the safety of others or the care of equipment must check every installation on a regular basis and perform all necessary maintenance. 3. All applicable instructions should be read and complied with before using any fluid power system in order to prevent harm to persons or equipment. In addition, overhauled or serviced valves must be functionally tested prior to installation and use. 4. Each ROSS product should be used within its specification limits. In addition, use only ROSS parts to repair ROSS products. WARNING: Failure to follow these directions can adversely affect the performance of the product or result in the potential for human injury or damage to property. FILTRATION and LUBRICATION 5. Dirt, scale, moisture, etc. are present in virtually every air system. Although some valves are more tolerant of these contaminants than others, best performance will be realized if a filter is installed to clean the air supply, thus preventing contaminants from interfering with the proper performance of the equipment. ROSS recommends a filter with a 5-micron rating for normal applications. 6. All standard ROSS filters and lubricators with polycarbonate plastic bowls are designed for compressed air applications only. Do not fail to use the metal bowl guard, where provided, to minimize danger from high pressure fragmentation in the event of bowl failure. Do not expose these products to certain fluids, such as alcohol or liquefied petroleum gas, as they can cause bowls to rupture, creating a combustible condition, hazardous leakage, and the potential for human injury or damage to property. Immediately replace a crazed, cracked, or deteriorated bowl. When bowl gets dirty, replace it or wipe it with a clean dry cloth. 7. Only use lubricants which are compatible with materials used in the valves and other components in the system. Normally, compatible lubricants are petroleum based oils with oxidation inhibitors, an aniline point between 80 F (8 C) and 0 F (04 C), and an ISO 3, or lighter, viscosity. Avoid oils with phosphate type additives which can harm polyurethane components, potentially leading to valve failure which risks human injury, and/or damage to property. AVOID INTAKE/EXHAUST RESTRICTION 8. Do not restrict the air flow in the supply line. To do so could reduce the pressure of the supply air below the minimum requirements for the valve and thereby cause erratic action. 9. Do not restrict a valve s exhaust port as this can adversely affect its operation. Exhaust silencers must be resistant to clogging and must have flow capacities at least as great as the exhaust capacities of the valves. Contamination of the silencer can result in reduced flow and increased back pressure. WARNING: ROSS expressly disclaims all warranties and responsibility for any unsatisfactory performance or injuries caused by the use of the wrong type, wrong size, or an inadequately maintained silencer installed with a ROSS product. POWER PRESSES 0. Mechanical power presses and other potentially hazardous machinery using a pneumatically controlled clutch and brake mechanism must use a press control double valve with a monitoring device. A double valve without a self-contained monitoring device should be used only in conjunction with a control system which assures monitoring of the valve. All double valve installations involving hazardous applications should incorporate a monitoring system which inhibits further operation of the valve and machine in the event of a failure within the valve mechanism. ENERGY ISOLATION/EMERGENCY STOP. Per specifications and regulations, ROSS L-O-X and L-O-X with EEZ-ON operation products are defined as energy isolation devices, NOT AS EMERGENCY STOP DEVICES. All products sold by ROSS CONTROLS are warranted for a one-year period [with the exception of STANDARD WARRANTY all Filters, Regulators and Lubricators ( FRLs ) which are warranted for a period of seven years] from the date of purchase to be free of defects in material and workmanship. ROSS obligation under this warranty is limited to repair or replacement of the product or refund of the purchase price paid solely at the discretion of ROSS and provided such product is returned to ROSS freight prepaid and upon examination by ROSS is found to be defective. This warranty becomes void in the event that product has been subject to misuse, misapplication, improper maintenance, modification or tampering. THE WARRANTY EXPRESSED ABOVE IS IN LIEU OF AND EXCLUSIVE OF ALL OTHER WARRANTIES AND ROSS EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES EITHER EXPRESSED OR IMPLIED WITH RESPECT TO MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. ROSS MAKES NO WARRANTY WITH RESPECT TO ITS PRODUCTS MEETING THE PROVISIONS OF ANY GOVERNMENTAL OCCUPATIONAL SAFETY AND/OR HEALTH LAWS OR REGULATIONS. IN NO EVENT IS ROSS LIABLE TO PURCHASER, USER, THEIR EMPLOYEES OR OTHERS FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES WHICH MAY RESULT FROM A BREACH OF THE WARRANTY DESCRIBED ABOVE OR THE USE OR MISUSE OF THE PRODUCTS. NO STATEMENT OF ANY REPRESENTATIVE OR EMPLOYEE OF ROSS MAY EXTEND THE LIABILITY OF ROSS AS SET FORTH HEREIN. ROSS CONTROLS USA Tel: Tech. Svs TEK-ROSS / Cust. Svs GET-ROSS web site: ROSS EUROPA GmbH Germany Tel: web site: ROSS ASIA K.K. Japan Tel: web site: ROSS UK Ltd. UK Tel: web site: ROSS SOUTH AMERICA Ltda. Brazil Tel: vendas@rosscontrols.com ROSS CONTROLS INDIA Pvt. Ltd. India Tel: ross.chennai@rosscontrols.com ROSS CONTROLS (CHINA) Ltd. China Tel: web site: www: rosscontrolschina.com ROSS FRANCE S.A.S. France Tel: web site: ROSS CANADA Canada Tel: (46-5-ROSS) web site: ( CANADA INC. An Independent Representative) Printed in the U.S.A. Rev. 08/6 06 ROSS CONTROLS. All Rights Reserved. Form PRD-37 Content subject to change.